Today's healthcare practitioners are usually provided with medical devices that are ready to use, because the devices are sterilized during manufacture. This is particularly true of syringes that are used to administer parenteral drugs and other medical solutions. A syringe typically includes a plastic barrel having a substantially closed end and an opposite open end. The open end is sealed by a slidable piston plunger. The closed end of the syringe has a dispensing port communicating with a male luer fitment, for dispensing the contents of the syringe. The syringe, as manufactured, may be prefilled with a liquid, part-filled with a lyophilized powder, or empty, for example. A removable end cover, such as a luer cap is placed over the luer fitment during manufacture so as to seal the contents within the barrel. Prefilled syringes are advantageous in avoiding confusion whether a vial is multidose or single dose, or confusion regarding which diluent should be used with a given lyophilized or powder medicament, and may provide a suitable housing for storage and shipping of sensitive pharmaceuticals such as biologics. Furthermore, use of prefilled syringes, particularly those with safety mechanisms, limits health professionals exposure to used syringes, inadvertent needlestick injuries, and possible exposure to infective pathogens or other contaminants.
Because of the increasing demand for prefilled syringes, there is a proportional increasing need syringes that are made or materials resilient to degradation or interaction with the pharmaceutical or other agent held within the syringe. Additionally, there are filled-on-demand substances that are not compatible with existing plastic syringes. In an attempt to overcome these issues, many syringe manufacturers have returned to the manufacture of glass syringes or syringes in which at least the barrel is glass. Current commercial versions of glass syringes have glass tips that are housed within plastic adapter structures for connection to syringes or other delivery means. These glass syringes have several disadvantages: the tips are fragile and may break during preparation or use, leading to potentially dangerous sharps; the syringes leak around imperfect seals between the glass and the adapter; plastic adapter structures may spontaneously disconnect from the glass tip; or the tips may clog due to the narrow nature of the configured glass tips.
Further, in developing syringes with luer connections, relatively complicated luer assemblies have been devised that are often adapted for a particular syringe barrel shape or configuration and cannot be readily mounted to a syringe barrel having a different shape or configuration. This is particularly a problem with glass syringe barrels which are generally in short supply, many of which glass barrels do not have a desired shape or configuration for mounting a luer assembly. Alternatively, the syringes may be manufactured with a pre-formed luer assembly, but this adds substantial complexity and cost to the process for manufacture of such syringes. Therefore, there is increasing demand for resilient syringes with adequate luer connection adapters.
Additionally, the practice of sharing syringes without adequate sterilization between successive users is a major contributor to the transfer of Human Immunodeficiency Virus and Hepatitis with subsequent severe repercussions for the sufferer and at a high cost to society for supporting and providing medical attention to sufferers. In response to this problem, syringes have been developed with the aim of preventing syringe re-use. One solution has been to develop syringes where the needle is permanently retractable into the barrel of the syringe, in which retraction may be driven by a compressed spring. Generally, spring decompression is relatively uncontrolled such that, in use, the excessively forceful needle retraction can result in blood splattering when air is forced from the syringe barrel as the needle retracts into the barrel. Therefore, there is a need for more “user friendly” retractable syringes that do not compromise the safety features provided by the syringe.